A wireless device can request authentication to establish communication with a communication network. When the wireless device is authorized, the wireless device can transmit and receive information over the network. Depending on location, the wireless device can communicate over a plurality of networks where each network is associated with a different network operator. For example, the network operator associated with the wireless device (e.g. a primary operator) may not be available in the area where the wireless device is located for various reasons such as network congestion or decreased coverage. In this case, the primary operator can have an agreement with a second operator to allow the wireless device to transmit and receive information using the second operator's network (e.g. “roam”).
Communication networks can generally support various types of communications such as interconnect (full-duplex) and push-to-talk (half-duplex) communications as well as a variety of data services. When a wireless device attempts to register on a secondary operator's network using push-to-talk communications, the primary operator's network can authorize such connection when the access node of the secondary operator is included in a pre-approved list (e.g. blacklist or whitelist) of roaming access nodes. If the access node of the secondary operator is not an approved access node, authorization will be denied and the wireless device can experience an undesirable interruption in service.